Person: Martín Cereceda, María Mercedes
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First Name
María Mercedes
Last Name
Martín Cereceda
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Biológicas
Department
Genética, Fisiología y Microbiología
Area
Microbiología
Identifiers
6 results
Search Results
Now showing 1 - 6 of 6
Item Rain-fed granite rock pools in a national park: extreme niches for protists(Limnetica, 2021) Pérez Uz, María Blanca; Velasco González, Ismael; Murciano, Antonio; Sánchez Jiménez, Abel; García-Rodriguez, M.; Centeno Carrillo, Juan de Dios; Montero González, Esperanza; Muñoz Araújo, Benito; Olmedo Salinas, Cristina; Quintela Alonso, Pablo; Refoyo Román, Pablo; Williams, Richard Alexander John; Martín Cereceda, María MercedesRain-fed granite rock pools are geological landforms with a worldwide distribution. However, their role as habitats for microorganisms has been barely explored. We carried out a detailed morphological inventory of the ciliated protists in the sediments of three granite rain-fed rock pools from a Spanish National Park. The ciliate seed bank in the rock pools comprised 54 morphospecies. The species number inferred for each pool by rarefaction analysis was similar to that observed by microscopy. The most representative species were small bacterivorous ciliates, although the distribution of ciliate groups was significantly different in each rock pool. Testate amoebae were also found to be rich in species. This study demonstrates the existence of a diverse ciliate community adapted to persist in these ephemeral and extreme rock pool habitats through species resistance structures, many of which have not been described previously. The presence of competitive species in dormant stages prevents local extinctions through a sequential excystation over time. Our results provide a benchmark for studying protist and microbial biodiversity within rain-fed granite rock pools, a unique habitat that merits bio- and geo- conservation.Item An investigation of the fine structure, cell surface carbohydrates, and appeal of the diatom Extubocellulus sp. as prey for small flagellates(Protoplasma, 2007) Martín Cereceda, María Mercedes; Williams, Richard Alexander John; Guinea Díaz, Almudena; Novarino, GianfrancoThe fine structure and surface exopolymers of a coastal planktonic nanodiatom of the sparsely reported genus Extubocellulus were studied respectively by scanning electron microscopy and confocal microscopy in conjunction with fluorescent lectins. Monitoring the suitability of the species as prey food for other protists was also investigated by video microscopy coupled with digital film. Cells are rectangular in girdle view, with a pervalvar axis longer than the apical axis. Valves are almost circular with a diameter of 2.8 to 3.6 m. The valve face bears randomly distributed areolae (ca. 50 in 10 m), which may be either open or occluded. Two small raised ocelluli occur at the apices, with a rim devoid of perforations and about 6–7 porelli. Glucose and N-acetylglucosamine moieties present on the surface of the live diatom were labelled with fluorescent lectins, and a differential pattern of distribution for both carbohydrates was observed. The potential role of fluorescent lectins as cellular probes of taxonomic value in small diatoms is compared with that of nucleotide and antibody probes. We provide the first illustrative evidence of the presence of Extubocellulus sp. in the cytoplasm of the nanoflagellate Goniomonas amphinema and of the egestion of diatom frustules. Results obtained are discussed in the light of the present knowledge of the role of carbohydrate–protein interactions in phagocytosis of prey by free-living protozoa.Item Diversity of DNA Sequences from Pathogenic and Potentially Pathogenic Eukaryotic Microorganisms in Protected Granite Mountain Rocks(Diversity, 2023) Murciano Cespedosa, Antonio; Pérez Uz, María Blanca; Williams, Richard Alexander John; Sánchez Jiménez, Abel; Martín Cereceda, María Mercedes; Velasco-González, Ismael; Lara, Enrique; Singer, David; de Cos-Gandoy, Amaya; García-Rodríguez, ManuelRain-fed mountain granite rock basins are temporary habitats conditioned by a fluctuating environment and the unpredictability of precipitation or flooding rates. These small highland freshwater habitats remain largely unexplored at the microbial level. The aim of this work is to report the presence in these habitats of genetic sequences of microbial eukaryotes that are pathogens and potential pathogens of humans, wildlife, cattle, crops as well as of other microorganisms. We sequenced the hypervariable region v4 of the 18S rDNA gene from environmental DNA of sediments taken from 21 rock basins in a National Park in Spain. More than a fifth (21%) of the eukaryotic Operational Taxonomic Units (OTUs) found are ascribed to pathogenic (within 11 Phyla) and potential pathogenic (within 1 phylum, the Chytridiomycota) microorganisms. Some OTUs retrieved are of agro-economic and public health importance (e.g., Pythium spp., Lagenidium spp., Candida spp. and Vermamoeba vermiformis). In 86% of the basins, the most abundant OTUs were affiliated to Chytridiomycota, a broad fungal group including saprozoic and parasitic taxa. Two OTUs affiliated to chytrids were significantly correlated with high concentrations of heavy metals. The high proportion of chytrid-like microbial sequences found emphasises the role of these freshwater habitats for adding knowledge regarding the ecological trade-offs of the still rather unknown Chytridiomycota. Our results show that rain-fed rock basins may be model habitats for the study and surveillance of microbial community dynamics and genetics of (mainly opportunistic) microbial pathogens.- Project number: PIMCD69/23-24
Item Esto va de Micro: 10 retos, 10 mujeres(2024) Gil Serna, Jessica; Arregui García-Roves, Lucía; Ayllón Santiago, Tania; Casado Almarcha, Ana María; Craqui Cordeo, María de la Vega; Domenech Lucas, Miriam; García Romero, Sofía Ismerai; Gómez Albarrán, Carolina; Gómez Rodríguez de Guzmán, Lucía; Lago Espartero, Darío; Lizarazu Cubero, Carolina; Martín Cereceda, María Mercedes; Melguizo Ávila, Clara Del Carmen; Patiño Álvarez, Aurora Belén; Pavesio Toledano, Manuel; Pérez Uz, María Blanca; Pulido Vadillo, Mario; Racovita, Georgiana Valentina; Rey Menacho, Rubén; Sánchez López-Varela, Marta; Tajahuerce Ángel, Isabel; Valderrama Conde, María José; del Valle Romera, Ana; Vázquez Estévez, María Covadonga Inmaculada; Williams, Richard Alexander John“Esto va de Micro” es un pódcast de microbiología en el cual estudiantes de la Universidad Complutense realizan entrevistas a personas expertas en temas de interés en el campo de la microbiología. En el curso 2023/2024 quisimos aprovechar esta plataforma y poner en marcha este proyecto de innovación docente para dar visibilidad al trabajo de microbiólogas relevantes y explicar a la sociedad el papel de la microbiología en la consecución de los Objetivos de Desarrollo Sostenible. El resultado han sido 11 episodios de pódcast divulgativos que están disponibles en las plataformas de iVoox y Spotify. Item Easy Visualization of the Protist Oxyrrhis marina Grazing on a Live Fluorescently Labelled Heterotrophic Nanoflagellate(Current Microbiology, 2008) Martín Cereceda, María Mercedes; Williams, Richard Alexander John; Novarino, GianfrancoPlanktonic heterotrophic flagellates are ubiquitous eukaryotic microorganisms that play a crucial role in carbon and nutrient fluxes through pelagic food webs. Here we illustrate for the first time a grazing model of planktonic dinoflagellate, Oxyrrhis marina, on the heterotrophic nanoflagellate Goniomonas amphinema, using the DNAbinding fluorescent dye Hoechst 33342. A solution of 1 lg/mL of the fluorochrome allowed viability of the prey for at least 48 hours, provided low fluorescence quenching, and labelled the flagellate without masking the cytoplasm. After 2 hours of contact between the fluorescent prey and the predator, O. marina population had preyed on live G.amphinema at an ingestion rate of 2.2 prey Oxyrrhis-1 h-1. Results show that this model is a time-effective and inexpensive approach for the direct observation of heterotrophic flagellate grazing. The fact that prey remain alive while predation occurs, as well as the low rate of quenching, could be of help in studying the fate of realtime trophic interactions between protists in microbial webs.Item Endemicity and climatic niche differentiation in three marine ciliated protists(Limnology and Oceanography, 2018) Williams, Richard Alexander John; Owens, Hannah L; Clamp, John; Peterson, A Townsend; Warren, Alan; Martín Cereceda, María MercedesThe biogeographic pattern of single-celled eukaryotes (protists), including ciliates, is poorly understood. Most marine species are believed to have a relatively high dispersal potential, such that both globally distributed and geographically isolated taxa exist. Primary occurrence data for three large, easily identified ciliate species, Parafavella gigantea, Schmidingerella serrata, and Zoothamnium pelagicum, and environmental data drawn from the National Oceanic and Atmospheric Administration’s World Ocean Atlas were used to estimate each species’ spatial and environmental distributions using Maxent v3.3.3k. The predictive power of the models was tested with a series of spatial stratification studies, which were evaluated using partial receiver operating characteristic (ROC) statistics. Differences between niches occupied by each taxon were evaluated using background similarity tests. All predictions showed significant ability to anticipate test points. The null hypotheses of niche similarity were rejected in all background similarity tests comparing the niches among the three species. This article provides the first quantitative assessment of environmental conditions associated with three species of ciliates and a first estimate of their spatial distributions in the North Atlantic, which can serve as a benchmark against which to document distributional shifts. These species follow consistent, predictable patterns related to climate and environmental biochemistry; the importance of climatic conditions as regards protist distributions is noteworthy considering the effects of global climate change.